Messages in this thread | | | Subject | Re: [PATCH] document mmiowb and readX_relaxed a bit more in deviceiobook.tmpl | From | Benjamin Herrenschmidt <> | Date | Sat, 30 Oct 2004 12:35:56 +1000 |
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On Fri, 2004-10-29 at 17:47 -0700, Jesse Barnes wrote: > This is a small patch to deviceiobook.tmpl to describe the new mmiowb routine > a bit more completely. I've also updated it to provide pointers to drivers > that do write flushing, use mmiowb, and use the readX_relaxed routines.
It's all good, but your semantics and description are very tailored to your specific arch problem vs. unlock.
What about my suggestion of defining a broader semantic of mmiowb() as beeing a barrier ordering MMIOs vs. the rest of the world ? The later includes stores to memory _and_ spinlock/unlock.
I still intend to eventually make good use of that on ppc64 to get rid of the expensive barriers we had to put in our writeX() implementations, though I didn't have time to work on that yet.
Ben.
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